The present invention relates to image sensors and, more particularly, to lens shielding structures for image sensors.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Compact camera modules may be produced using wafer-scale processing. In a typical water level optics arrangement, image sensors are fabricated from a silicon wafer. Wafers of glass and other substances are used to form lenses and support structures. Camera modules may be formed by mating one or more wafers of optical, components such as lenses with a wafer of associated digital image sensors. During packaging operations, the wafers are separated into, individual sensors and are mounted in corresponding, plastic packages. Forming camera modules in this way can be highly economical, because wafer-level mass production techniques allow many sensors and associated lenses to be formed in parallel.
To reduce flare and thereby improve image quality, cameras are often provided with lens hoods. For example, cone-shaped and petal-shaped lens hoods are sometimes mounted to the lenses of single lens reflex cameras. Camera modules that are formed using wafer level optics and wafer level packaging arrangements are also sometimes provided with light shielding structures that serve as miniatures lens hoods. These, structures generally have a truncated cone shape having a wider circular end and a narrower circular end. The narrower circular end of the cone is formed adjacent to the outermost lens in the camera module. The wider circular end of the cone forms an exit aperture.
Although conventional lens shielding structures such as these may help improve optical performance by reducing lens flare, it is not always possible to reduce flare as much as desired.